From: "Maciej S. Szmigiero" Subject: Re: [PATCH 2/3] crypto: ccp - return an actual key size from RSA max_size callback Date: Sat, 3 Mar 2018 00:58:18 +0100 Message-ID: <7deb1115-b4b2-8fe3-885f-0162f2fe359f@maciej.szmigiero.name> References: <51c265e4-6153-3e5e-316a-ebef059ac36a@maciej.szmigiero.name> <20180302164451.GJ21579@gondor.apana.org.au> <087e7b27-f839-8d4b-8da8-5d0fa2f8caf1@maciej.szmigiero.name> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Herbert Xu , "David S. Miller" , David Howells , Tom Lendacky , Gary Hook , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org To: "Hook, Gary" Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 03.03.2018 00:49, Hook, Gary wrote: > On 3/2/2018 5:15 PM, Maciej S. Szmigiero wrote: >> On 02.03.2018 17:44, Herbert Xu wrote: >>> On Sat, Feb 24, 2018 at 05:03:21PM +0100, Maciej S. Szmigiero wrote: >>>> rsa-pkcs1pad uses a value returned from a RSA implementation max_size >>>> callback as a size of an input buffer passed to the RSA implementation for >>>> encrypt and sign operations. >>>> >>>> CCP RSA implementation uses a hardware input buffer which size depends only >>>> on the current RSA key length, so it should return this key length in >>>> the max_size callback, too. >>>> This also matches what the kernel software RSA implementation does. >>>> >>>> Previously, the value returned from this callback was always the maximum >>>> RSA key size the CCP hardware supports. >>>> This resulted in this huge buffer being passed by rsa-pkcs1pad to CCP even >>>> for smaller key sizes and then in a buffer overflow when ccp_run_rsa_cmd() >>>> tried to copy this large input buffer into a RSA key length-sized hardware >>>> input buffer. >>>> >>>> Signed-off-by: Maciej S. Szmigiero >>>> Fixes: ceeec0afd684 ("crypto: ccp - Add support for RSA on the CCP") >>>> Cc: stable@vger.kernel.org >>> >>> Patch applied.  Thanks. >> >> Thanks. >> >> However, what about the first patch from this series? >> Without it, while it no longer should cause a buffer overflow, in-kernel >> X.509 certificate verification will still fail with CCP driver loaded >> (since CCP RSA implementation has a higher priority than the software >> RSA implementation). >> >> Maciej >> > > > I commented on that one here: > https://marc.info/?l=linux-crypto-vger&m=151986452422791&w=2 > > Effectively a NACK. We are a reviewing a proposed patch right now. Your earlier comment referred to the third patch from this series. My message above was about the first one. Maciej